OBJECTIVE: To examine whether amyloid PET in CN individuals that were screened for the Anti-Amyloid in Asymptomatic AD (A4) study differed across self-identified, non-Hispanic White and Black (NHW and NHB) groups.METHODS: We examined 3689 NHW and 144 NHB that passed initial screening for the A4 study and underwent amyloid PET. The effect of race on amyloid PET was examined using logistic (dichotomous groups) and linear (continuous values) regression controlling for age, sex, and number of APOE epsilon4 and APOE epsilon2 alleles. Associations between amyloid and genetically determined ancestry (reflecting African, South Asian, East Asian, American, European populations) were tested within the NHB group. Potential interactions with APOE were assessed.RESULTS: NHB had lower rates of amyloid-positivity and lower continuous amyloid levels compared to NHW. This race effect on amyloid was strongest in the APOE epsilon4 group. Within NHB, those with a lower percentage of African ancestry had higher amyloid. A greater proportion of NHB did not pass initial screening compared to NHW, suggesting potential sources of bias related to race in the A4 PET data.CONCLUSION: Reduced amyloid was observed in self-identified non-Hispanic Blacks that passed initial eligibility criteria for the A4 Study. This work stresses the importance of investigating AD biomarkers in ancestrally diverse samples as well as the need for careful consideration regarding study eligibility criteria in AD prevention trials.
View details for DOI 10.1212/WNL.0000000000011599
View details for PubMedID 33568538